JSON is trash and should never be used in any human-interfacing context, so I'm super skeptical that there's any utility in trying to fix it; that would just delay its demise, to the detriment of humankind.

But if you did want to fix JSON, the yes, trailing commas and comments are the absolute minimum bar, but single quote is actually probably the the third absolute must-fix.

The reason is just that so much JavaScript tooling is now configured to autoformat code (including the JSON bits) to swap " to ', thanks in large part to Prettier (which also should almost never be used, sigh, but that's a topic for another HN bikeshed...)

hexadecimal identifiers, yeah, nah